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MG MGB Technical - Indicator/headlamp stalk switch melted

Hi everyone,

Was recently driving my 72' mgb roadster at night and was shocked when smoke started to billow out of the steering column cowl... slightly worried i pulled over, but by that time it had stopped smoking. Got home and had a closer inspection and found that headlights no longer worked. Side lights/indicators and everything else electrical seems fine, fuses are ok also.

Taking off the cowl cover i found that the connection on the far right of the stalk switch was fried (blue/red wire). I dont know whether this is a common problem, have been some postings regarding fried connections, do i need to investigate further or should replacing this connection solve my problem? Do i need to check my ground connections?

Thanks in anticipation
Roderick Dixon

Hi Roderick.

The blue / red wire does feed the dipped headlamps.

I assume that the smoke was from melting wire insulation, I would take a good look to assess the extent of the melting.

If the melting is only local it seems likely that a connection had gone 'high resistance' which would result in local heat build-up (resulting in smoke), followed by melting of the remainder of the copper wire at the high resistance point, which would then result in the heat build-up stopping and the dipped headlights going out. Re-connecting the wire (after making good any burned insulation on the blue / red and any adjacent wires) may be all that is needed, assuming the the switch wasn't damaged by the heat.

If the blue / red wire's insulation is melted along a significant part of it's length it could be that you have a short to chassis at some point along the wire's length, probably where it has chafed when passing a sharp edge or something. This would require further investigation, but insert an inline 15A fuse near the switch before thinking of re-connecting.

If the main beams don't work there is probably wiring damage on the 'input' side of the switch.

Don't forget to disconnect the battery while working on the (unfused) headlamp circuits.

Please let us know how you get on.

HTH.. Don
Don

Thanks for the prompt reply Don,

Looks like the wire is only melted at the connection point, dont know if i will beable to salvage the switch though, looks a bit messy... will let you know what happens.
Roderick Dixon

This thread was discussed on 31/08/2005

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